export function hasClass (el, className) {
    let reg = new RegExp('(^|\\s)' + className + '(\\s|$)')
    return reg.test(el.className)
}

export function addClass (el, className) {
    if (hasClass(el, className)) {
        return
    }
    let newClass = el.className.split(' ')
    newClass.push(className)
    el.className = newClass.join(' ')
}

export function removeClass (el, className) {
    if (hasClass(el, className)) {
        var reg = new RegExp('(\\s|^)' + className + '(\\s|$)')
        el.className = el.className.replace(reg, '')
    }
}